A number of patients will have breast biopsies because of irregular mammograms and palpable abnormalities. Biopsies can include surgical excisional biopsies and stereotactic and ultrasound guided needle breast biopsies. In the case of image directed biopsy, the radiologist or other physician may take a small sample of the irregular tissue for laboratory analysis. If the biopsy proves to be malignant, additional surgery (typically a lumpectomy or a mastectomy) may be required. In the case of needle biopsies, the patient may return to the radiologist a day or more later, and the biopsy site (the site of the lesion) may need to be relocated in preparation for the surgery. An imaging system, such as ultrasound, magnetic resonance imaging (MRI) or x-ray may be used to locate the biopsy site. In order to assist the relocation of the biopsy site, a marker may be placed at the time of the biopsy.
The state of the art technology for conducting a breast biopsy is to use a vacuum-assisted breast biopsy device. A current textbook in this area is “Vacuum-Assisted Breast Biopsy with Mammotome®”, available Nov. 11, 2012, copyright 2013 by Devicor Medical Germany GmBh, published in Germany by Springer Medizin Verlag, Authors: Markus Hahn, Anne Tardivon and Jan Casselman, ISBN 978-3-642-34270-7.
A biopsy marker may comprise hydrogel, such as described in “Evaluation of a Hydrogel Based Breast Biopsy Marker HydroMARK® as an Alternative to Wire and Radioactive Seed Localization for Non-Palpable Breast Lesions” by Rebecca L. Klein et al.; Journal of Surgical Oncology 2012; 105: 591-594, the contents of which are incorporated herein by reference.
Additional details regarding hydrogel are described in “Hydrogel: Preparation, characterization, and applications: A review” by Enas M. Ahmed; Journal of Advanced Research (2015) 6; 105-121, the contents of which are incorporated herein by reference.
The use of hydrogel materials for markers used after breast biopsies to mark the location where the biopsied tissue was removed is described and claimed in the following US Patents: U.S. Pat. No. 6,083,524, “Polymerizable biodegradable polymers including carbonate or dioxanone linkages” issued Jul. 4, 2000; U.S. Pat. No. 6,162,241, “Hemostatic tissue sealants”, issued Dec. 4, 2000; U.S. RE39713, “Polymerizable biodegradable polymers including carbonate or dioxanone linkages issued Jul. 3, 2007; U.S. Pat. No. 6,270,464, “Biopsy localization method and device”, issued Aug. 7, 2001; U.S. Pat. No. 6,356,782, “Subcutaneous cavity marking device and method”, issued Mar. 12, 2002; U.S. Pat. No. 6,605,294, “Methods of using in situ hydration of hydrogel articles for sealing or augmentation of tissue or vessels”, issued Aug. 12, 2003; U.S. Pat. No. 6,790,185, “Sealant plug delivery methods”, issued Sep. 14, 2004; U.S. Pat. No. 8,320,993 “Subcutaneous cavity marking device”, issued Nov. 27, 2012; U.S. Pat. No. 8,600,481, “Subcutaneous cavity marking device”, issued Dec. 3, 2013 and U.S. Pat. No. 8,939,910, “Method for enhancing ultrasound visibility of hyperechoic materials”, issued Jan. 27, 2015. All of these US Patents are incorporated by reference in their entirety.
U.S. Pat. No. 8,939,910, “Method of Enhancing Ultrasound Visibility of Hyperechoic Materials”, issued on 27 Jan. 2015 and assigned to Devicor Medical Products, Inc., the contents of which having previously been incorporated herein by reference, describes a hydrogel marker that is enhanced by air cavities within the hydrogel that reflect under ultrasound imaging in different way than the reflection of the hydrogel, thereby making it easier to detect the hydrogel marker. Such air cavities in the enhanced hydrogel are hypoechoic and thus serve to further indicate the location of the marker. U.S. Pat. No. 8,939,910 gives an example of creating air cavities using inserts of differing sizes and shapes. The inserts are placed in the hydrogel during the manufacturing process and removed from the hydrogel after it is cured, leaving air-filled cavities in the hydrogel marker. The cavities are air-filled and reflecting differently under ultrasound imaging from the reflection of the hydrogel and making the hydrogel easier to detect under ultrasound.
In some contexts, a marker element is disposed within a bioabsorbable carrier. In these contexts, it may be desirable to enhance the visibility of the carrier under ultrasonic visualization. One method of enhancing visualization of the carrier is impregnating the carrier with a plurality of microbubbles. However, some difficulties have been encountered with uniformly distributing microbubbles of a sufficient size throughout the carrier. Accordingly, in some contexts, it may be desirable to enhance a biopsy site marker by uniformly distributing microbubbles of a sufficient size throughout a carrier. While several systems and methods have been made and used for marking a biopsy site, it is believed that no one prior to the inventor has made or used the invention described in the appended claims.
The drawings are not intended to be limiting in any way, and it is contemplated that various embodiments of the invention may be carried out in a variety of other ways, including those not necessarily depicted in the drawings. The accompanying drawings incorporated in and forming a part of the specification illustrate several aspects of the present invention, and together with the description serve to explain the principles of the invention; it being understood, however, that this invention is not limited to the precise arrangements shown.